This invention relates to electromechanical switches, and more particularly, to controls that are primarily used in complex signal systems for monitoring and controlling the flow of vehicular and railroad traffic or industrial processes including electric utilities, petrochemical, water treatment and materials handling systems.
Design engineers and manufacturers of both large and small control panels are continually striving to maximize the amount of control function they can provide within the smallest amount of panel space. In addition to the cost savings achieved by using less mechanical equipment and a smaller amount of floor space, higher density control panels allow an operator to view and control more functions for a given amount of space and therefore require fewer personnel to operate.
The majority of traffic flow control systems interface with programmable logic controllers that actually direct traffic flow control situations. Customers are generally not interested in having redundant spare switches in case of a failure. This is because there are now multiple electrical/electronic system driven safety backups should an electrical circuit malfunction for any reason. Also, wiring is both heavy and expensive and duplicate function spare wires consume too much space in panels. Because spare wires also consume connector and terminal block space and the labor to assemble them, wire cables and harnesses to these controller switches carry the fewest number of individual wires necessary for the required signals. Rewiring of connectors or harnesses to access backup switch modes in a controller switch is neither practical nor reliable once a panel is completely installed in the field.
Today, designers are more interested in circuit flexibility and maximizing the number of circuit functions that can be accessed for a given panel space. Design engineers also often prefer to identify certain specific operating motions to circuit activation. Perhaps, as an added safety feature to prevent inadvertent operation, a designer may require an operator to pull or push and then quickly turn a knob before a circuit can operate. Conversely, the designer may require a specific degree of rotation to activate a specific circuit or require a circuit be momentary in one direction of rotation and maintained or latching in the opposite direction of rotation.
It is an object of the invention to provide a switch.
A further object is to provide a switch capable of push only, pull only, push-pull, left turn, right turn, left and right turn, or push-pull left turn right turn combinations of action.
Another object is to provide a switch capable of maintained switch action, momentary switch action, or combinations of both in any switch with multiple positions.
Still another object is to provide a switch which can incorporate multiple means of mounting, multiple means of signal wire termination, an extensive variety of circuit possibilities, and an array of multiple LED illumination capability packaged in the smallest possible controller switch footprint available today.
Yet another object of the invention is to provide a control panel switch which provides for an improvement in panel density and an increase in signal functions per cubic volume of panel space, thereby providing customers with unparalleled cost savings.
In view of the above considerations, the present invention provides a modular family of multi-function high circuit density controls that can realize a range of specific types of circuits and actions that can be easily matched to the needs of particular applications. The invention can be used in a family of controls that can be adapted to a variety of behind panel depth limitations while still providing the maximum number of discrete circuits for a given cubic volume of space. The control density provided by the invention is unmatched by any currently available device or series of devices.
The modular concept of a switch according to the invention is to allow them to be easily replaced in a panel or grid system by removing one nut and disconnecting the plug connector. A new switch can be quickly mounted in the grid or panel, and the malfunction unit can be repaired at a remote site.
A switch according to the invention allows for push only, pull only, push-pull, left turn, right turn, left and right turn, or push-pull left turn right turn combinations of action, with the switch actions being maintained, momentary, or combinations of both in any switch with multiple positions. The Switch incorporates multiple means of mounting, multiple means of signal wire termination, an extensive variety of circuit possibilities, and an array of multiple LED illumination capability packaged in the smallest controller switch footprint available today. The resultant improvement in panel density and signal functions per cubic volume of space provides customers with unparalleled cost savings.
Switches incorporating the present invention are designed around a single unit base structure with a simple xe2x80x9cdrop-in designxe2x80x9d mechanical operating mechanism that allows for interchangeable mounting bushings and operating shafts of various lengths for different panel or grid/title thickness"". All switches feature either cable or connector control wire termination and the xe2x80x9cdrop-inxe2x80x9d electrical switching contact elements can be varied to customize individual control circuit requirements. The design provides for simple, but unique, precise operating shaft and control surface stops to insure that millions of operating cycles will be possible under severe field conditions.
By incorporating all of the push/pull/turn forms of action into a primary internal shaft support bearing the overall length of the control is reduced while a higher level of protection from the elements is achieved. That is, external control open areas which allow dust and dirt to enter moving parts are eliminated by encapsulating the shaft and its associated switch modules within a common enclosure.